From 2009 to 2013, the birthrate for teenagers fell a staggering 40 percent, and abortion rates dropped by 43 percent. There were similarly drastic results for unmarried women under 25 who have not completed high school, another group vulnerable to unplanned pregnancies. The privately-funded program was particularly effective in the poorest areas of the state.

The results come six years after the Centennial state initiated an experimental program that offered teenagers and poor women free long-acting birth control like intrauterine devices (IUDs) and implants that could prevent pregnancy for years. Women in Colorado reacted enthusiastically towards the program, and its results spoke volumes about the compelling argument for free contraception.

Greta Klingler, the family planning supervisor for the Colorado Department of Public Health and Environment, told The New York Times:

Our demographer came into my office with a chart and said, 'Greta, look at this, we've never seen this before.' The numbers were plummeting.

Teenagers across the country are becoming pregnant with less frequency, but Colorado in particular is seeing a more forceful decline.

"This initiative has saved Colorado millions of dollars," Governor John Hickenlooper said in a statement last year. "But more importantly, it has helped thousands of young Colorado women continue their education, pursue their professional goals and postpone pregnancy until they are ready to start a family."

The state's health department is currently seeking more funding for the program.

The private grant that the program runs on is quickly running out, but despite its proven success, Colorado's socially conservative lawmakers don't plan on allowing it to continue on public funds. The Guardian reports that last year, the state's Republican-controlled Senate voted to block public funding for the program.

"Unfortunately, family planning is a political issue and science and data gets trumped by ideology," Klinger told The Guardian. "It's a missed opportunity for the people of Colorado, many of whom still don't have access to the best most effective methods and services out there ... [The program has] shown to save the state an enormous amount of money, so there's the economic piece of this too."